1. Field of the Invention
The present invention relates to an ink jet printer, and, more particularly, to a waste ink accumulation system for an ink jet printer.
2. Description of the Related Art
Ink jet printers require maintenance operations to keep the nozzles of the print cartridge operating properly. Such maintenance operations typically include the steps of wiping the nozzle area of the print cartridge, firing the nozzles at prescribed intervals to purge the nozzles (spitting), and capping the cartridge during idle periods to prevent the jetted ink which remains on the nozzle plate from drying and clogging one or more of the nozzles of the nozzle plate. Typically, the spitting operation occurs at a location in the maintenance station. Over a period of time, the solids in the waste ink accumulate in the maintenance station, and the resulting waste ink buildup can affect the operation of the maintenance assembly.
It is possible for a stalagmite of dry waste ink to form in the base of the ink well in the maintenance station. The waste ink is the result of normal operation of an ink jet printer. As the height of the stalagmite grows, it can at some point interfere with the maintenance sled or print cartridge causing failure in the printer. The chance of failure due to such a stalagmite has greatly increased in recent years due to the rise in the number of nozzles in a print cartridge and higher frequency of maintenance. In the past, printers have used a felt pad to absorb the waste ink, which is sufficient for slow drying inks and/or low solid content in the ink, but it is not sufficient for fast drying and high solid content inks.
In a waste ink accumulation system, the waste ink migrates to wherever the ink originally dries. The surface area available for drying is limited to the inner surface of the body for accumulating the inks. In addition, the ink begins forming solid piles of ink as it accumulates and dries. A problem is that if the printer is not level, or the printer is tipped, the ink piles can tip, fall out and cause contamination to other parts of the printer.
What is needed in the art is a waste ink accumulation system that prevents the growth of ink stalagmites and that prevents piles of waste ink from falling out of the waste ink receptacle.
The present invention provides a system including a horizontally rotating cup for catching waste ink from an ink jet printer and redistributing it around a spiked body of the cup. The cup is rotated using the energy of the printhead carrier during normal operation. The rotating cup is designed such that the waste ink builds in a circular fashion around the body of the cup rather than building on a center point, thus preventing the formation of a stalagmite.
The rotating waste ink accumulation system is a passively energized system whereby the energy to actuate the system is provided by the normal primary function of the printer.
The system uses a horizontally rotating cup to catch the waste ink. The cup is designed with teeth to rotate systematically as a gear while freely riding a rub ring on the body of the cup. The horizontal rotation distributes the ink in a large area to prevent stalagmite formation at a central point.
The cup has a matrix of spikes to provide both larger surface area for ink migration and also a skeletal system for the dried waste ink, which prevents tipping of ink piles.
The cup is rotated in a ratcheting motion by an actuator wall, using a cylindrical plunger and receiving hole to restrict the direction of motion. The actuator wall is self-resetting to avoid adding any energy to the primary operation of the printer. The actuator wall is driven by the carrier-driven maintenance sled feature as the printhead carrier goes into the maintenance station capping position (in-stroke) and out of the maintenance station capping position, which freely releases the actuator wall, all staying within a linear motion.
The invention comprises, in one form thereof, a waste ink accumulation system in an ink jet printer. A rotatable body has an ink-collecting surface and a plurality of projections extending from the ink-collecting surface. An actuating mechanism rotates the body.
An advantage of the present invention is that the buildup of waste ink is prevented, thus avoiding functional failure of the primary maintenance system.
Another advantage is that the waste ink accumulation system is passively energized. The energy drawn from the primary function of the printer is negligible. Therefore, no energy source is required to be to be added to the base printer via motor, solenoid or any other means.
Yet another advantage is that the spikes in the base of the cup aid in holding the ink mounds from rolling out of the cup when the printer is tilted.